The present invention relates to a locking mechanism resistant to pressures and utilized for locking doors of switching cells of a switching device or switching board.
The locking mechanisms of the foregoing type have been required to effectively absorb overpressures caused by electric arc short circuit in the switch field and to thereby protect personnel and the switch plant. Since the doors,particularly for high voltage switching cells are subject to very large pressure forces occurring due to the above described effect these forces are very difficult control. Conventional hinges and locks can not withstand to such pressure forces and can be damaged by an arc short circuit. Thus pressure waves and hot arc gases can spread outside of the switching cell and lead to damages.
A housing for an electric device has been proposed, the doors of which are locked by a key-bolt or a locking bar against the action of explosive pressures occurring within the housing of the electric device. A pressure-resistant locking device for flat doors closing high-voltage switching cells, formed of sheet material,is known, in which a locking bar extends over the entire length of the door edge,and the door is secured against pressure increase from inside. Such a locking device is disclosed in DE-PS No. 1,465,529. The locking bar is applied to the closing side and also to the hinge side of the door. The pivotable locking bars must be locked depending on respective functions of the switching cell. There is, however, a danger that an operator may forget to lock such a locking bar.